Pointer question (long)

["Goodbar, Loyd (AFS-Water Valley)" <LGoodbar@xxxxxxxxxxxxxx>]

Using the MD5 program found at <http://www.as400pro.com/TipsRPG7.htm>, I'm
trying to convert it to a generic subprocedure to be used by any ILE
program. I want to pass a pointer to the data to be encrypted, as not to
pose any length restrictions.

I created a prototype to the procedure like this:
d MD5             pr            32a
d  inputdata                      *   value
d  inputlength                  10i 0 const

and a procedure interface like this:
p MD5             b
d MD5             pi            32a
d  inputdata                      *   value
d  inputlength                  10i 0 const

I changed these lines in the MD5 program:
* removed references to MSG
* removed SOURCEPTR
* changed these lines:
c                   eval      datalength = inputlength
 * Change message to ccsid 819 (ascii)
c                   callp     convert(%addr(inputdata) : %addr(to819) :
c                             inputlength)
 * Get MD5
c                   callp     cipher( %addr(receiverptr) : %addr(controls)
c                             : %addr(inputdata) )

FYI, the supplied MD5 program uses the following prototypes, MI I believe:
d cipher          pr                  extproc('_CIPHER')
d                                 *   value
d                                 *   value
d                                 *   value
d convert         pr                  extproc('_XLATEB')
d                                 *   value
d                                 *   value
d                               10u 0 value

In my test program, I have this:
d mymd5           s             32a   inz
d testmsg         s            250a   inz
d testlength      s             10i 0 inz
c                   eval      testmsg='message digest'
c                   eval      testlength=%len(%trimr(testmsg))
c                   eval      mymd5=MD5(%addr(testmsg):testlength)
c     mymd5         dsply

My problem is this:
Running in debug, I see a valid pointer for INPUTDATA upon entering the MD5
subprocedure.
After this line executes, however:
c                   callp     convert(%addr(inputdata) : %addr(to819) :
c                             inputlength)
INPUTDATA has a *NULL pointer, and the call to CIPHER fails with the error
"Pointer not set for location referenced."

In the original program, the call to CONVERT was made using a pointer to
variable MSG, and calling CIPHER with another pointer to variable MSG. I am
calling CONVERT with a pointer to INPUTDATA, and call CIPHER with the same
pointer to INPUTDATA.

I believe that is my problem, and I need to create a second pointer to
INPUTDATA to use with CIPHER. How do I do that?

Thanks,
Loyd

--
Loyd Goodbar
Programmer/Analyst
BorgWarner Incorporated
Air/Fluid Systems, Water Valley, MS